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IS38 1.8T Info/Discussion

Armchair Racer

Go Kart Champion
Location
Florida
This is pretty much normal of any car that gets traction from a standstill. The rate of acceleration and longitudinal G-forces are almost always higher from a launch than from a roll.

I have the IS20 stock Downpipe tune from APR and feel the same way. It feels like it is a completely different car from a launch then from a roll. Sometimes if I catch it just right from a roll it feels insane but it isn't like that most of the time. I was JB4 + IS20 stock Downpipe and at times I feel like it was faster from a roll with that set up. Hard to tell but nephew seems to agree with me. Definitely much faster from a launch than the JB4 set up was.
 

Armchair Racer

Go Kart Champion
Location
Florida
Did you see the last photo he posted? That's not a melted piston! That's a fatigued/failed piston. Here's what a melted piston looks like:

http://i1053.photobucket.com/albums/s472/takedown1976/Carnage/IMG_0091_zps166c6f9a.jpg

There are no signs of hot spots or a meltdown condition in any of the piston photos that have been posted of the failed 1.8T thus far. The photos are consistent with George Smooth's post that it failed from too much stress over time.

The piston melted. Wasn’t cracked or anything.


Sent from my iPhone using Tapatalk
 

Armchair Racer

Go Kart Champion
Location
Florida
Okay so it appears you may be the king of BS here lol. I just did a little research into RJ's GTI. Here are a few details which you conveniently left out:

1) In the video you're referencing he's running much taller drag radials so his speedo is off by a whopping 5%. That's huge. So when the video shows him at 100, he's actually only doing 95.

2) He didn't go 11.1@127 like you said. He went 11.1@125.9. However if you check his Instagram post from the day he ran the 11.1, you'll see there was a problem with the right lane at the strip... it was off by 3-4 MPH compared to the left lane. In the left lane all his traps were 122-123.

3) The speedo video of his car was taken BEFORE the meth and 11.1 pass. He was only trapping 118-120 at the time the video was taken.

These are all reasons why bench racing and comparing videos online just doesn't work. Run your car at the strip. I bet you'll trap mid to high teens. Again, that's still fast for a 1.8T wagon.
 

TwinDad

Autocross Newbie
Location
Fort Lee, NJ
You're not getting that the 1.8 is proving itself to be able to make more power than the 2.0. The 2.0 uses a 4mm larger crank journal, has larger counterweights on the crank, and has a longer stroke. That with the vvti, which is not better for performance, makes it produce more low end power, but fall off fast. Most of that power is not seen once out of first. At the shift points the 1.8 is making more power and will make more power after that and higher in the band. The APR tunes are not maximized for all out power like on the 2.0. That's why Chuck and Ironshade have had great results with a stack. If you don't believe it, my JB4 is20 car beat my friends JB4 gti by a couple of car lengths. He is peaking at 26psi and tapering to 18. In only 22-18. And I'm a sportwagen. Full weight with pano sunroof
 

TwinDad

Autocross Newbie
Location
Fort Lee, NJ
On also laughing about how a 5spd is all of a sudden horrible for racing when it was a game changer in the world of 3spd and 4sp guys. I guess my 400 Firebird than ran a 12.1 with a 3spd was a fluke 30 years ago. I guess no one told it about the future and the dsg.
 

Armchair Racer

Go Kart Champion
Location
Florida
Are you joking with that first sentence? How do figure that the 1.8T is "proving" to make more power than the 2.0T? You're correct that Chuck had great results but his car is also completely gutted running an open downpipe with no catback, front slicks etc. Even still, he's nowhere near the 125+ traps that both 2.0T Golf Rs and GTIs have ran with OEM IS38 turbos. With all else equal the 2.0T will always make more power than the 1.8T due to the better cam profile, larger displacement among other reasons. That is just a fact.

You're not getting that the 1.8 is proving itself to be able to make more power than the 2.0.The 2.0 uses a 4mm larger crank journal, has larger counterweights on the crank, and has a longer stroke. That with the vvti, which is not better for performance, makes it produce more low end power, but fall off fast. Most of that power is not seen once out of first. At the shift points the 1.8 is making more power and will make more power after that and higher in the band. The APR tunes are not maximized for all out power like on the 2.0. That's why Chuck and Ironshade have had great results with a stack. If you don't believe it, my JB4 is20 car beat my friends JB4 gti by a couple of car lengths. He is peaking at 26psi and tapering to 18. In only 22-18. And I'm a sportwagen. Full weight with pano sunroof
 

Armchair Racer

Go Kart Champion
Location
Florida
You're making very general and vague arguments here which has nothing to do with what we were talking about. Some of the quickest RWD muscle cars in the world run 2 and 3-speed automatic transmissions. What's your point? It has nothing to do with the number of gears but rather the gearing. The gearing of the 5-speed transaxle in the FWD 1.8Ts is absolutely horrible. It's a HUGE difference compared to the 6-speed DSG in the Sportwagen 4Motion. Here's an example of why it will hurt acceleration in a big way. When you shift from say 2nd to 3rd with the 5-speed, you'll be at a MUCH lower RPM at the start of third. Now look at an IS38 1.8T dyno sheet and you'll see at that lower RPM the engine is making significantly less power than it is at the MUCH higher RPM where the DSG trans will be at the start of 3rd after the 2-3 shift. This results in slower acceleration. There's no disputing that.

As others have noted, the 5-speed is not a close ratio box. It has long ass gears and as such, will hurt acceleration, especially with a decent sized turbo like the IS38 which shifts the powerband higher compared to the IS20 and factory IS12.

On also laughing about how a 5spd is all of a sudden horrible for racing when it was a game changer in the world of 3spd and 4sp guys. I guess my 400 Firebird than ran a 12.1 with a 3spd was a fluke 30 years ago. I guess no one told it about the future and the dsg.
 

Armchair Racer

Go Kart Champion
Location
Florida
Take a look at 613B6's A3. He trapped 120 on PUMP gas, no meth, in a full interior and full exhaust A3 with OEM IS38. That's a much heavier setup than Chuck G's gutted SW with no catback and other weight reduction. PLUS there's an enormous difference between pump/no meth and race gas/meth yet he still went 120 compared to Chuck's 119.

I love the 1.8T and own one but it's getting pretty deep in here... You shouldn't make bogus posts like the one below because others will read it and think it's true. It's absolutely positively a false statement. The 2.0T with all else equal will always make more power than the 1.8T for several different reasons such as displacement and cam profile.

You're not getting that the 1.8 is proving itself to be able to make more power than the 2.0.
 

crxgator

Autocross Champion
Location
Raleigh, NC
Car(s)
All the MQBs
Did you see the last photo he posted? That's not a melted piston! That's a fatigued/failed piston. Here's what a melted piston looks like:

http://i1053.photobucket.com/albums/s472/takedown1976/Carnage/IMG_0091_zps166c6f9a.jpg

There are no signs of hot spots or a meltdown condition in any of the piston photos that have been posted of the failed 1.8T thus far. The photos are consistent with George Smooth's post that it failed from too much stress over time.


again, it's a melted piston. The picture of the piston removed shows that it melted. The picture has not been posted. Cylinder 1 didn't get enough fuel. Go look in the jb4 thread for more details.
 

TwinDad

Autocross Newbie
Location
Fort Lee, NJ
The quickest awd 2.0 cars are right in the 1/4 mile thread. Race gas, weight reduction, meth etc. They are running 11.4-11.5@114-115. So tell me again how Chuck isn't as fast as they are on a make do tune. Get some facts straight first.
 

TwinDad

Autocross Newbie
Location
Fort Lee, NJ
And the 1.8 uses an identical intake cam. Only the exhaust cam is different because of vvti. That vvti and exhaust cam is why the gti can't hold as much boost or power up top like the 1.8. Combine that with shorter stroke and less reciprocating mass, the 1.8 has the ability to make more power. This isn't just a VAG thing, it applied to all engines. Once we figure out the hpfp issue and maybe get some custom tunes, you will truly see. The weak point on the 1.8 now becomes things like pistons and possibly the bottom end. Keep talking from your armchair until you go out and actually try
 

Armchair Racer

Go Kart Champion
Location
Florida
Again, yet another flawed argument. While those may be the fastest AWD 2.0T cars which are posted on this website they aren't representative of the 2.0T IS38 cars that are pushed hard. Like I said, there are Golf Rs and GTIs that have trapped mid 120's with full exhausts (Chuck was running an open exhaust). I also gave you the A3 example, a pump gas, no meth, full exhaust and much heavier car that still trapped higher than Chuck.

Again, it was a ridiculously false statement to make.

The quickest awd 2.0 cars are right in the 1/4 mile thread. Race gas, weight reduction, meth etc. They are running 11.4-11.5@114-115. So tell me again how Chuck isn't as fast as they are on a make do tune. Get some facts straight first.
 

Armchair Racer

Go Kart Champion
Location
Florida
So now you're saying it has the _ability_ to make more power once certain things are changed. Just before you said it already has proven to make more power than the 2.0T. So which is it?

The reason why the GTI can't hold more boost up top is because it has greater displacement. The fact is due to the better head, cam profile and greater displacement, it will always make more power than the 1.8 with all else equal. It's a silly argument anyway since the 1.8T is weaker and shouldn't be pushed to these limits anyway due to the weaker pistons and cast crank.

And the 1.8 uses an identical intake cam. Only the exhaust cam is different because of vvti. That vvti and exhaust cam is why the gti can't hold as much boost or power up top like the 1.8. Combine that with shorter stroke and less reciprocating mass, the 1.8 has the ability to make more power. This isn't just a VAG thing, it applied to all engines. Once we figure out the hpfp issue and maybe get some custom tunes, you will truly see. The weak point on the 1.8 now becomes things like pistons and possibly the bottom end. Keep talking from your armchair until you go out and actually try
 

TwinDad

Autocross Newbie
Location
Fort Lee, NJ
And I just checked the spreadsheet and the cars you're referring to are trapping 118-120 not 114-115 like you stated:

https://docs.google.com/spreadsheets/d/1K9e__fbEAtlsmvV1R6L5UPvxTtFibLlgcP9B7qrjv9U/htmlview

Sorry, I meant 118-119. The same trap and et that Chuck is running. So even with my error, he is just a short fast as the very fastest awd 2.0 in North America. All on a tune that's not supported to be that fast. So keep telling me how the 1.8 is not making just as much power or more.
 
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